1. Field of the Invention
The present invention is directed in general to communications systems and methods for operating same. In one aspect, the present invention relates to the methods, systems and devices for performing HARQ operations.
2. Description of the Related Art
Long Term Evolution (LTE) Advanced is a mobile communication standard currently under development for submission as a major enhancement of the 3GPP Long Term Evolution (LTE) standard to define an Evolved Universal Terrestrial Radio Access (E-UTRA) radio technology in which multiple simultaneous transport blocks can be used to send data from an E-UTRAN Node B (eNB) to a user equipment (UE) device. To address potential data transmission errors, a Hybrid Automatic Repeat Request (HARQ) scheme is defined in the existing LTE 3GPP standard which provides a combination of forward error-correcting coding and error detection coding using the HARQ error-control method to detect and correct data transmission errors. With existing HARQ schemes, incorrectly received coded data blocks may be stored in a soft buffer at the UE/receiver so that, when the retransmitted block is received, the received values for the two blocks may be combined. Unfortunately, conventional (Rel-8) approaches for dividing the soft buffer among downlink (DL) HARQ processes may result in inefficient HARQ operations and/or buffer utilization, particularly when data blocks are being transmitted over multiple aggregated carriers (Rel-10) which may not have identical channel and/or interference conditions and/or properties and/or when carrier-related transmission mode reconfiguration occurs.
As will be appreciated, there are challenges to using current HARQ schemes to partition the soft buffer among different HARQ processes, especially as the number and type of carriers increase with carrier aggregation techniques. Accordingly, a need exists for improved methods, systems and devices for managing downlink HARQ soft buffers to overcome the problems in the art, such as outlined above. Further limitations and disadvantages of conventional processes and technologies will become apparent to one of skill in the art after reviewing the remainder of the present application with reference to the drawings and detailed description which follow.